Persalts

Hydrogen peroxide reacts with some acids (sulphuric acid for instance) and forms peroxy-acida, and with some bases [such as Ca(OH2), Ba(OH)2, Mg(OH)2, Zn(OH)2] and forms peroxides. Oxides of the IV and VI group of the periodic system (i. e. oxides of Ce, Ti, V, Nb, Ta, Cr, Mo, W, U) also react with hydrogen peroxide to form peroxides, peroxy-acids and persalts. Many additive compounds of hydrogen peroxide are known such as with sodium metaborate, urea and hexamethylene-tetramine. 

A 30 or 40 per cent by volume hydrogen peroxide is used as bleach for silk, wood, Wool, bones, teeths, feathers, mother of pearl, hom, hair, coral, gelatine, oils and fats. In medical science it is an excellent disinfectant and is also essential for sterilizing water for municipal use and preserving milk. Apart from this, hydrogen peroxide is used in the chemical industries for the manufacture of persalts and in laboratories for oxidation. 

BURCOWHITE SM Conc. is an oxidative alkali, a dry peroxygen compound developed to be an ideal textile persalt. 

Catalytic activation of hydrogen condensed either in the palladium sponge or in the foil was disclosed in the same paper [15]. At the ambient temperature, persalt of iron became protosalt and chlorine-water was transformed into hydrochloric acid. 

Acrylamide grouts at ambient temperatures are catalyzed with a two-component redox system. One part, the initiator or catalyst, can be a peroxide or a persalt. Ammonium persulfate (AP), a powder, is most commonly used. The second part, the accelerator or activator, is an organic such as triethanolamine, (TEA), nitrilotrispropionamide (NTP), or dimethylaminiopropionitrile (DMAPN). All three have disadvantages. DMAPN, a liquid, is best from a control point of view but is considered a health hazard. NTP, a powder, has limited solubility in water, particularly at low temperatures. TEA, a liquid, is somewhat metal-sensitive. At the present time virtually all U.S. applications use TEA. There are also materials which act as inhibitors and can be used reliably to control gel time. Potassium ferricyanide, KFe, is most often used. 

Persait A salt containing a relatively large proportion of the acidic element or group as, the persalts of iron. 

Under optimized conditions, TAED shows a performance comparable to the corresponding per-oxyacetic acid (Figure 16.6). There is a negligible performance deficit at tanperatures below 40°C, based on delayed dissolution and perhydrolysis. Above 60°C, however, activator systems benefit from the excess of persalt, which contributes significantly to stain removal. 

When dissolved in water, perborate and percarbonate generate hydrogen peroxide. Although peroxoborates [62] and peroxocarbonates [63] are analytically detectable in such solutions, under normal usage conditions both persalts deliver comparable bleaching results. 

Historically, European washing powders contain high amounts of persalts. Even after the introduction of activator technology, formulations with more than 20% perborate were state of the art. From the stoichiometric point of view (for complete perhydrolysis of one molecule of TAED, two... 

WO 99/00481 (1999) A. Meyer et al., Procter Gamble Bleach activators, persalts Nonaqueous hquid detergent comprising organic acid to reduce solubihty of bleach system... 

Multiaction powders with <50% persalt, but with special ingredients, such as optical brighteners, photobleaches, enzymes, or dye transfer inhibitors... 

For pretreatment of stains, bleach activators in stick form are claimed [193], consisting of a water-soluble surfactant binder and TAED powders. The activator is applied directly on the stain before the wash process and activated by a persalt-containing detergent. A similar concept based on single-dosed laundry boosters was used some time ago in Europe. It comprised a nonsoluble sheet of nonwoven material, which contained a high amount of bleach activator but no peroxide source [194]. To work, the sheet had to be added to persalt-containing detergents. 

Note Total H2O2 production figures include material used for persalt production, but this is conventionally omitted from % breakdown of applications of H2O2 itself. 

Many synthetic polymers are treated with H2O2 to reduce colour or odour and, sometimes, to increase long-term stability. Among these can be mentioned poly(fluoroolefins) [290], polyvinyl alcohol [291], polyethylene [292] and polybutadiene [293]. Optical lens resins can be made more transparent by using persalts [294]. 

This is the basis for the use of the solid forms of H2O2, that is, persalts such as sodium perborate (PBS) and sodium percarbonate (PCS). 

Persalts is a term that is used to refer to solid H2O2 carriers, that is, those products that release H2O2 on dissolution in water. These include PBS and PCS. 

Percarboxylic acids are stronger oxidizing agents than hydrogen peroxide or persalts. Their general strnctnre is R-COjH, where R = an organic moiety. 

Granulation ingredients used include carboxymethylcellulose [48] and surfactants [49]. Stabilizers can also be added in some grades to enhance compatibility with persalts in the detergent formulation. 

---